A fixing device includes a fixing belt, a pressuring roller pressured to the fixing belt, a heat source heating the fixing belt, a pressing member pressing the fixing belt toward the pressuring roller's side, and a sliding contact sheet interposed between the fixing belt and the pressing member to hold lubricant. The sliding contact sheet includes a sliding contact portion arranged at the center in a sheet conveying direction to come into contact with the fixing belt, a first fixed portion arranged at an upstream side in the conveying direction and wound around the pressing member at the heat source's side, and a second fixed portion arranged at a downstream side in the conveying direction and wound around the pressing member at the heat source's side from the first fixed portion. The sliding contact sheet is configured so that the second fixed portion becomes smaller than the first fixed portion.